How would i rig up shielding gas on the inside of a pipe

[tommy dunlop]

Hi all,whats the best way to purge the inside of a stainless pipe,can i T" of my tig,i also have a bottle of argo light,could i just hook that up to the inside the pipe to be weldded,i would like to do it so when i hit the pedle the two go together,i hate waisting gas,what sort of cfm would i need to purge,is it the same as the torch,thanks tom

 

[Gosh14]

The best option is to put splitter next to regulator and flow meters on each hose connection.
If you are about saving a gas then there is plenty of "if`s" involved. If you weld 4" 6mm thick on 2.4 gap then you can reduce purge flow from 10 to 5 ltrs but to cover unwelded area with masking tape and punching a holes in a cap at the other end of the pipe at the final stage of the root. For different pipe size (like 2" 1.5mm) slightly different saving rules apply.

 

[tommy dunlop]

cheers,i was looking at a 3/8 splitter on ebay,i was thinging about splitting on the hose that runs up the torch,but then again i dont want to pull that about,thanks tom

 

[Engineer]

I guess you are welding something to do with the food industry? If not there is no real need for purging, unless its something where the inside of the pipe will be visible after welding.

 

[hotrodder]

But if you let the back of the weld oxidise (aka 'coked' or 'sugared' weld) the result is more likely to be stainmore instead of stainless as there'll be less chromium available to do it's 'thing'. Crevices from partial pen welds or coked welds can lead to crevice corrosion in some environments

Several threads on purging in the TIG forum, one here... http://www.mig-welding.co.uk/forum/showthread.php?t=12621&highlight=purge Flow rates and purge time depends on the size of the thing. Assuming all joints/gaps are taped up then if we're talking smallish diameter thin wall tube (no root gap) then the purge can be turned to a trickle once established. Heavier wall with a root gap and you'll need higher flow rates to keep the air out.

Argoshield light isn't suitable.

 

[Engineer]

The OP was asking about SS pipe to repair an exhaust a few days ago. Not completely sure I would want to purge an exhaust system repair?

 

[tommy dunlop]

hi thanks for the replys
it is for a manifold,turbo 14gauge 304, i was thinking it would give a bit more strenght to the inside wall,i can grind the inside wall,but i need this as strong as poss,them turbos make good power,but they are like a bag of sandthanks for all advice i am all ears,tom

 

[Engineer]

14G seems a bit heavy for a manifold? Have you had much experience of this type of work I wonder?

 

[the snooper]

i wouldnt have thought 1.6mm to heavy for a manifold especially holding a turbo

 

[tommy dunlop]

thanks for the reply,i am just goning to replace what i cut out,like for like,not my chioce to use 14g,thanks tom

 

[tommy dunlop]

this is like the one i have to repair,before some one attacked it with a mig welder and messed it up,tom

 

[Engineer]

i wouldnt have thought 1.6mm to heavy for a manifold especially holding a turbo

14swg = 2.03mm.............

 

[Engineer]

thanks for the reply,i am just goning to replace what i cut out,like for like,not my chioce to use 14g,thanks tom

Should be fine then..........what was the original problem I wonder?

 

[the snooper]

14swg = 2.03mm.............

yeah you're right calculation wrong

 

[tommy dunlop]

some one lent it,then said it wont fit in there car,so they cut n shut it,i will post photos of what it looks like at pressant,tom

 

[Engineer]

Been attacked by a numpty then...............pretty common complaint!

 

[hotrodder]

With turbo EGTs there ain't any margin for error if 16 or 14swg 304/316 is used for the manifold. Definately wants purging, very common to find cracks quickly propogating from welding flaws

 

[tommy dunlop]

messed up manifold

this was a real bit of craftman ship before they hit it with a mig welder with mild steel wire,got to cut all the mig out replace it with stainless,buzz it back with tig,mind destroying lol